The invention relates to the field of snapping rollers for corn harvesting combines and more specifically to the structure and manufacturing of a high capacity roller suitable for high speed picking of sweet, field and seed corn under a wide range of crop moisture levels and adverse weather and field conditions. A method for making the new roller is also disclosed.
Corn harvesting combines utilize one or more pairs of headers positioned forwardly of the combine, with each pair of headers engaging a row of upright corn stalks therebetween as the combine moves forward Each such pair of headers has a pair of rotating, cooperating snapping rollers with outwardly extending blades or protrusions which endeavors to grip the corn stalks therebetween and pulls the stalks downwardly while the corn ears are removed. It is crucial that, until the corn ears are removed, the stalk not be severed by the rollers because the stalk must be gripped by the rollers and pulled downwardly through the rollers in order to snap off the corn ears against plates positioned above and adjacent the snapping rollers. Should any stalk be cut or broken above the rollers, the remaining upright portion of the stalk and any corn ears on it will either fall away to the side of the combine and be lost in the field or both the corn ears and the attached stalk will fall into the combine. It is important to prevent such stalks from entering the combine screens with the picked ears because the unwanted stalks and leaves produce extra wear on internal combine parts, more clogging and overall less efficient operation when such trash and residue must be processed through the combine. As the ears are removed from the stalk, the stalk is pushed downwardly toward the ground by the rollers and dropped in the field to eventually dry out and decompose.
Ideally, no stalks should enter the combine screens with the ears and they should be discarded in the wake of the combine. Since the discarded stalk residue must usually be cut or chopped up before new plowing or seeding can be done, it is desirable that the stalk undergo as much breakage and deterioration as possible during combining without allowing it to break before the ears are picked.
Since the invention of corn harvesting combines, many snapping roller designs have been developed. Most designs work satisfactorily when the combine moves at slow ground speeds in moderately dry corn and under reasonably dry field and weather conditions. As ground travel speed increases to the 3 to 8 m.p.h. range, the performance of now available rollers steadily, significantly deteriorates with increasing numbers of stalks breaking off before ear removal and either the entire stalk and ears being lost to the harvest or the broken stalks falling into the combine screening system. The faster the ground speed becomes, the more the snapping rollers clog up and more stalks break prior to corn ear removal.
Corn harvesting must often be done late in the growing season, just before freezing, and at times when weather is unpredictable at best. Often the crop is wet from rain, the field muddy, and cool temperatures allow little chance of rapid drying. Often the farmer must harvest his crop within a short time interval or risk its loss or deterioration due to worsening weather. When time is short, it can be essential to harvest even in rainy, wet field conditions, and it becomes important to be able to harvest at higher speeds under adverse field, weather and crop conditions.
Some corn crops, like sweet corn, are harvested when the stalks are still green and contain high levels of moisture. Such stalks are far more prone to slip during snapping roller engagement than are dryer stalks. Moist stalks are also more resistant to breakage. All varieties of corn differ in ways which affect snapping roller performance, as for example moisture content, stalk thickness, ear size, ear placement, and fiber consistency of the stalk, any of which can help or hinder snapping roller operation. Moisture conditions of individual corn stalks may vary widely even on a single farm, with stalks in low areas being wet and those on higher ground being dry. Since many of these parameters change so rapidly as to be unknown or unpredictable, it is important that snapping rollers be able to operate at higher speeds under most conditions that will be encountered, and regardless of the crop's moisture level or specific physical characteristics.
As optimum picking performance by the snapping rollers is achieved, it is desirable to also have the rollers achieve a high level of mutilation and breakage of stalk residue after the ears have been removed, so as to minimize subsequent independent stalk cutting steps with disks, specialized stalk shredders and the like, since plowing and seeding for the next crop cannot begin until the stalks are well broken up and decomposed. Prior art rollers have generally been unsuccessful in destroying the stalk residue and the farmer must make repeated passes with disks and shredders to prepare the field for plowing In some specialized crop situations, it is essential to produce dramatic stalk destruction with the rollers In the seed corn industry, it is required that rows of male corn plants be promptly and completely destroyed after fertilization has been accomplished, and an improved snapping roller would be helpful.
Designing a snapping roller capable of high capacity operation in wet, muddy, field conditions and which works for most corn varieties over a full range of dry and moist stalk conditions has been challenging to designers, with most designs showing promise at low to moderate speeds and dry conditions but failing increasingly at high speed operation under wet field and stalk conditions. It has been difficult to predict the performance of roller designs without extensive testing under widely varying weather, crop and speed conditions Even slight mechanical changes in a roller are capable of producing unexpected changes in corn picking and handling.
Always complicating the designing of the roller is that the roller must be aggressive enough to firmly grip the stalks and pull them downward under all speed, weather, crop and stalk moisture conditions so as to pick the corn ears without damaging the ears. After successful picking, it should badly mutilate and break the stalks. However, the roller cannot be so aggressive that it severs the stalk, breaks the stalk, or loses control of the stalk before the ears are removed. Satisfying these contradictory parameters makes design difficult and unpredictable.
Many variations of snapping roller configurations are known to the art and utilized in corn harvesting. Most snapping rollers have a central, one piece cylindrical steel core, and outwardly extending stalk engaging blades are then attached to the cylindrical core. Snapping rollers of this type are expensive to manufacture because they must be provided with apertures and slots in the core for connecting the rollers to the drive shafts of the combine and these apertures and slots must usually be drilled or milled because the cylindrical steel cores are not suitable for a stamping operation.
Snapping rollers have also utilized square cross section, elongated central cores, with flat blades being bolted to each side of the core to obtain a roller with four blades extending outwardly and spaced at 90` intervals. These structures tend to clog under high speed operation or with high moisture corn stalks, and such clogging results in the stalks breaking off before the ears can be removed. This configuration and variations of it are shown in U.S. Pat. Nos. 2,604,750 and 3,100,491, the '491 patent illustrating snapping rollers having L-shaped brackets which carry one or two blades bolted to a cylindrical core.
Another snapping roller configuration, shown in U.S. Pat. No. 4,233,804, utilizes a hexagonal cross section core and attaches three U-shaped cutting blades with such blades being bolted to three alternate faces of the hexagonal core to provide six outwardly extending blades A variation, of this mounting arrangement is shown in U.S Pat. No. 2,538,965 in which U-shaped blades are mounted to a round cross sectional core.
Still a further known snapping roller configuration utilizes a round central core with outwardly extending, longitudinally raised nubs. While this arrangement is effective with dry stalks, it incurs slippage and loses more and more stalks as speeds increase or stalk moisture levels rise. It is highly desirable to reduce slippage between the rollers and the stalks, because with reduced slippage, it is possible to attain higher ground speeds and harvest the corn.
The most effective known high speed capacity snapping roller for handling stalks under a wide range of moisture, field, and weather conditions is snapping roller 11 of FIG. 1 wherein a hollow, cylindrical core 13 has ten outwardly extending blades 15 which cooperate with a second similar, but mirror imaged roller to grip the corn stalks therebetween The roller 11 was developed by the assignee of the present invention.
Each blade 15 is attached to the core 13 at approximately a 45 degree angle by front and rear welds 17 and 19, with the welds 17 being spaced intermittently along the length of the front surface 21 of each blade and the welds 19 spaced intermittently along the length of the rear surface 23 of each blade. These blades 15 extend along the full length of the cylindrical core, and the assembly and welding of such blades to the core is time consuming and labor intensive. The blades cannot be welded to the core continuously all along the intersections between the blade and the core, because the required high welding temperatures warp and distort the blades badly. Consequently, intermittent welds are used, and, even then, welding temperatures produce blade warp and distortion. Such distortion and warping result in non-parallel blades 15, non-parallel blade edges 31, irregular spacing between blades, and non-uniform angles between blade and core. The many required, rough welds 17 which are positioned quite centrally in the channels between adjacent blades 15, will snag corn stalk fibers and encourage stalk residue buildup on the roller. The inventor believes that when large quantities of stalks are processed by the roller, the blades 15 flex at both the cutting edges 31 and along the core 13 between the intermittent welds. This flexing causes the channels between blades to enlarge and contract, and the bottleneck effect of a narrowing channel will cause clogging, slippage and lost stalks. Despite these problems, this blade structure is more resistant to clogging than most other rollers and until the present invention worked better than other known rollers at all speeds, crop and weather conditions, as well as being more destructive of the stalk residue.
The roller 11 is attached to the drive shaft of a combine by sliding the drive shaft within the aperture 33 between elements 37 and 39 of split collar 41 which is fixed to the inside of the cylindrical core 13 near the middle of the roller. A gap 43 is provided between elements 37 and 39 to allow tightening of the elements against the drive shaft. In order to permit the elements 37 and 39 to converge toward the drive shaft, it is necessary to mill a short pair of slots 29 through the core 13 parallel to the central longitudinal axis of the roller 11. Such milling must be done after assembly of the roller 11 and is slow, costly and labor intensive. It is also necessary to drill and mill access slots 45 and 47 in the core 13 and blade 15, respectively, to allow insertion and turning of machine bolts 60 into threaded apertures 27 of the collar 41. At the front end of the roller 11, a transverse aperture must also be drilled in the core to receive a roll pin which passes through the core, through a front internal collar and through the drive shaft. All such cutting is time consuming and drives the cost of the roller 11 upward. The new invention described hereafter avoids the expensive milling and drilling operations, simplifies manufacture of the roller and lowers its cost.